15m is up in the UK at the moment

I know we have been approaching the doldrums on HF but over the last couple of days 15 metres has been open and I've heard lots of DX. South Africa is coming in strong and South America is good too. At the time of writing 11:45 UTC 9th August 2016 it has become lively.

There is hope for DX yet so get your ears on and listen or if operating digimodes get the computer on!

HF Doldrums

Very little HF working in the last few days. Daytime working has been limited to occasional contacts on 20 metres. Early morning I've had a few 40 metre contacts. SFI is currently 73 with a K index of 4.
This is what approaching a solar minimum is like :(

2 Rigs 2 Antennas 2 Switches - Part 3

6m activity is very sporadic and as we are coming up to the Perseids maximum activity phase (August 12th 2015) then I have had chance to try out the switches in anger (so to speak). I heard a DXPedition station calling CQ on 6m from Aland Island (a rare DXCC island off the coast of Finland). I was on the dipole at the time and decided to switch over to the inverted Vee. Wow what a difference, before he was about RS52 perfectly readable. As soon as I threw both switches over to the Vee then he was coming in at RS57 occasionally peaking at RS59.

The new switching mechanism works a treat and is superb. Maybe my dipole is not that efficient!

I bet behind your computer and rigs it's a rats nest of cables like mine!

2 rigs 2 antennas 2 coaxial switches - Part 2

The Diamond CX-210A switches arrived along with some high spec 0.5m long patches leads terminated either end with PL259 plugs.

I cut a small piece of plywood on the table saw and mounted both switches side by side with the supplied screws. One of the patch leads was connected between the switches as per my circuit diagram outlined in Part 1.

The other two patch leads were used to connect to the two rigs. The antennas were then connected to the switches output as per the photo.

I placed the switch assembly board behind both rigs on the desk. In operation I just exercise a few muscles and get out of the shack chair to throw each switch! No need for it to be in finger tip reach.

The insertion loss for each switch is 0.05dB from DC to 500MHz and I have not noticed any issues with loss of sensitivity of either rig. I just worked a couple of stations in Argentina and Brazil (about 8000 miles away) on 35 watts PSK31 so neither transmission nor reception have been impacted. VHF/UHF on the FM transceiver is ok too with a distant repeater in Birmingham (about 72 miles away) still being workable on 2m.

2 rigs 2 antennas 2 coaxial switches - Part 1

I have a couple of antennas and 2 base station rigs. The FM transceiver is quad band and is attached to a tri band antenna covering 6m/2m/70cm. The HF antenna is connected to a multi band antenna covering 40m to 6m including all the WARC bands. It is supposed to be able to resonate on 80m band too but I've never had any success with this.

With this in mind the 6m portion of the VHF/UHF antenna (Diamond V-2000) is an inverted Vee that is directional - despite "visually appearing" to be part of a vertically polarized antenna system. The VHF and UHF portions of the antenna are omnidirectional vertically polarized. I have the 6m portion pointing eastwards.

At times of 6m activity it would be nice to switch between the conventional HF antenna to the W-2000 on the HF rig to see if there are any differences. It is very inconvenient to reach around the back of each of the rigs to unscrew the antenna plugs and swap them over so I came up with this idea.
Using a pair of Diamond CX-210A 2 way coaxial switches I designed the circuit shown below.

There is no interlocking so there can become an issue where rigs are connected to nothing on occasion. However the good news is that the output of one cannot be connected to the output of another! As this is going to be used just by me I see no problem. I just have to remember to throw both switches at the same time. 

The antenna switches are connected the conventional way (the HF rig feeding the common connection) of the HF switch. The FM transceiver is connected to one of the switched connections of the VHF/UHF switch. In normal operation each rig is connected to its respective antenna. When I want to use the HF rig on the V-2000 I have to throw both switches to their other positions. I would also switch the FM transceiver off as it wouldn't be connected to an antenna at all.

There doesn't appear to be anything relatively cheap on the amateur market that can do this so in the spirit of ham radio I'm doing it myself. The switches and connectors have been ordered - watch this space!

Noisy 20m band and quiet 15m band

I normally work the 20 and 15m bands in the morning through into the late afternoon. Over the last few months this has been really lucrative being able to work many countries during the day. Over the last couple of days 20m has developed a lot of atmospheric noise and 15m has become fairly quiet.

I hope the bands will improve otherwise I'll have to go back to VHF/UHF for a while :(